Fig. 2

Exemplary results from test-PCRs dnc1 (A) and dnc2 (B) performed on recovered ssDNA to determine the optimal number of cycles for subsequent amplification. In A, amplification of ssDNA recovered in round 3 of SELEX-3 (R3_SELEX) is shown alongside with the negative control (R3_NC) and the non-template control (NTC). The circle highlights the number of cycles (18) at which the peak of the fluorescence signal is reached while the three arrows point at the number of cycles (15, 16 and 17) before the peak which were chosen for testing in dnc2. In dnc1 the fluorescence signal was normalized to 0. In Figure B, L: ladder, 15, 16 and 17: PCR product after 15, 16 and 17 cycles